The present invention relates to gas and liquid contact installations.
Gas and liquid contact installations are employed for the cooling of a fluid, for example water, by means of atmospheric air. Generally, such installations comprise a heat exchange unit which is placed in an enclosure provided with an air inlet opening and an air outlet opening, and in which the water to be cooled is placed directly or indirectly in contact with the air between the air inlet and the air outlet from the enclosure. In the case of a direct contact heat exchange, the water is brought to the unit by a distribution system and is then sprayed or otherwise distributed on the heat exchange unit about which the air is passed. The latter may be constructed either in the form of an assembly of plates along which the water trickles in the form of thin films, or in the form of an assembly of surfaces which ensure the dispersion of the water in very fine droplets so as to form a mist which passes through the counter-current stream of air.
The heat exchange units are generally constructed from plastic materials, such as polystyrene, ABS, polyethylene, polypropylene or polyvinyl chloride These plastic materials are based on carbon and hydrogen and burn more or less easily. In the case of atmospheric coolers, fire dangers are insignificant when the cooler is in operation and supplied with water; this is not so when the exchanger is shut down and drained. Further, in the case of atmospheric coolers, or more generally gas and liquid contact installation in which the fluid to be cooled or placed in contact with the gas is not water, possibilities of fire may exist even when the installation is operating. It is consequently essential to provide means to prevent the spread of fire in such heat exchange units, which could result in unrepairable damage to the entire installation, and, also in the case where the exchange unit plates are formed of polyvinyl chloride, the emanation of highly toxic chlorinated compounds result from fires.